This is a bit off thread really...
But I think the newer meters also communicate via RF using some sort of XBee compatible protocol.
However I've not found any open source solutions, or a great deal of information about this.
I know that the you have to contact your electricity supplier and they have to authorize you meter to communicate with the XBee based device, I presume based on some serial number (in the XBee ??)
But this does seem the way that things are going and provides a lot more data i.e realtime power usage etc.